drm/amd/display: Check dce_hwseq before dereferencing it

[WHAT]

hws was checked for null earlier in dce110_blank_stream, indicating hws
can be null, and should be checked whenever it is used.

Cc: Mario Limonciello <mario.limonciello@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Hung <alex.hung@amd.com>
Signed-off-by: Aurabindo Pillai <aurabindo.pillai@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 79db43611ff61280b6de58ce1305e0b2ecf675ad)
Cc: stable@vger.kernel.org

diff --git a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
index e8730cc40edbe865e60cbb59d65e2942d66c124a..38e17b1796e18b5b6a912957de892bef601e9a6f 100644 (file)
--- a/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
+++ b/drivers/gpu/drm/amd/display/dc/hwss/dce110/dce110_hwseq.c
@@ -1225,7 +1225,7 @@ void dce110_blank_stream(struct pipe_ctx *pipe_ctx)
                return;
 
        if (link->local_sink && link->local_sink->sink_signal == SIGNAL_TYPE_EDP) {
-               if (!link->skip_implict_edp_power_control)
+               if (!link->skip_implict_edp_power_control && hws)
                        hws->funcs.edp_backlight_control(link, false);
                link->dc->hwss.set_abm_immediate_disable(pipe_ctx);
        }